For example, a centrifugal compressor sucks air as a compression medium, and causes the air to flow through an impeller and a diffuser that configure a compression mechanism, to gradually decrease a speed in a radial direction, namely, a centrifugal direction, thereby compressing the air. Accordingly, if temperature of the air to be sucked is low, a mechanism on an inlet side, in particular, of the compressor that sucks the air may be frozen, which may inhibit necessary operation of the mechanism. Examples of the mechanism include a mechanism driving an inlet guide vane (IGV) that regulates a flow rate of the air to be sucked into the compressor.
Patent Literature 1 proposes that a heat exchanger be provided in an intake chamber connected to a compressor of a gas turbine, and a portion of exhaust gas of the gas turbine be supplied to the heat exchanger.
Further, Patent Literature 2 proposes that, to prevent inlet side of the compressor of the gas turbine from being frozen, high-temperature compressed air extracted from an outlet of the compressor be guided to the inlet side of the compressor to increase inlet temperature of the compressor.
As described above, Patent Literature 1 and Patent Literature 2 are both to prevent freezing by heated air.